In the formation of absorbent articles for bodily excretions, one continuing problem is that the bodily excretions are usually directed at one portion of the absorbent pad, whereas the absorptive capacity is spread over a greater area. This may create an early failure problem if the exudate to be absorbed cannot be spread throughout the absorbent. If the fluid does not spread out through the absorbent, it may run off the edge of the saturated zone. Another disadvantage is that when the saturated absorbent in the primary flow area is compressed, for example when a person sits down, it may force the fluid out of the pad and cause rewetting. Such compression can also cause an overflow which can be uncomfortable to the wearer and which can result in stains to the undergarment.
Another problem to be overcome, in catamenial devices particularly, is that discharges can include fairly large pieces of tissue and blood clots that do not readily pass through a fine cover material. With sanitary napkins it would be desireable if the stained absorbent material did not exhibit the stains after absorption. It also would be desirable if feminine pads and other absorbent products could be visually examined to determine if they were almost saturated. Quite often with the absorption being into a target zone on the top of the pad and then spreading beneath the absorbent, it is not clear from top viewing when the pad is close to being saturated or when the target area is so close to being fully saturated that leakage may soon result.
In U.S. Pat. No. 4,423,101 issued to Willstead and French patent 1,477,127 issued to Cartiera Di Cairate, it is disclosed that the cover material may be perforated to aid in the passing of materials through the cover. In U.S. Pat. No. 4,480,000 issued to Watanabe et al. and U.S. No. 3,375,827 issued to Bletzinger et al., it has been proposed to interpose a layer between the permeable wrapper member and the main portion of the absorbent. Bletzinger et al. utilizes a compressed cellulosic material and indicates that the element spreads the exudate as it is absorbed.
There still remains a need for a pad that will provide even distribution of fluid within the pad, a cleaner surface to the pad, better concealment of fluid in the pad and less side leakage.